-<?xml version='1.0' encoding='UTF-8'?>
-<!-- This document was created with Syntext Serna Free. --><chapter xmlns="http://docbook.org/ns/docbook" xmlns:xl="http://www.w3.org/1999/xlink" version="5.0" xml:lang="en-US" xml:id="lustreoperations">
+<?xml version='1.0' encoding='UTF-8'?><chapter xmlns="http://docbook.org/ns/docbook" xmlns:xl="http://www.w3.org/1999/xlink" version="5.0" xml:lang="en-US" xml:id="lustreoperations">
<title xml:id="lustreoperations.title">Lustre Operations</title>
<para>Once you have the Lustre file system up and running, you can use the procedures in this section to perform these basic Lustre administration tasks:</para>
<itemizedlist>
<para><xref linkend="dbdoclet.50438194_88063"/></para>
</listitem>
<listitem>
+ <para><xref linkend="dbdoclet.lfsmkdir"/></para>
+ </listitem>
+ <listitem>
<para><xref linkend="dbdoclet.50438194_88980"/></para>
</listitem>
<listitem>
<indexterm><primary>operations</primary><secondary>mounting by label</secondary></indexterm>
Mounting by Label</title>
<para>The file system name is limited to 8 characters. We have encoded the file system and target information in the disk label, so you can mount by label. This allows system administrators to move disks around without worrying about issues such as SCSI disk reordering or getting the <literal>/dev/device</literal> wrong for a shared target. Soon, file system naming will be made as fail-safe as possible. Currently, Linux disk labels are limited to 16 characters. To identify the target within the file system, 8 characters are reserved, leaving 8 characters for the file system name:</para>
- <screen><fsname>-MDT0000 or <fsname>-OST0a19</screen>
+ <screen><replaceable>fsname</replaceable>-MDT0000 or <replaceable>fsname</replaceable>-OST0a19</screen>
<para>To mount by label, use this command:</para>
- <screen>$ mount -t lustre -L <file system label> <mount point></screen>
+ <screen>mount -t lustre -L <replaceable>file_system_label</replaceable> <replaceable>/mount_point</replaceable></screen>
<para>This is an example of mount-by-label:</para>
- <screen>$ mount -t lustre -L testfs-MDT0000 /mnt/mdt</screen>
+ <screen>mds# mount -t lustre -L testfs-MDT0000 /mnt/mdt</screen>
<caution>
- <para>Mount-by-label should NOT be used in a multi-path environment.</para>
+ <para>Mount-by-label should NOT be used in a multi-path environment or when snapshots are being created of the device, since multiple block devices will have the same label.</para>
</caution>
<para>Although the file system name is internally limited to 8 characters, you can mount the clients at any mount point, so file system users are not subjected to short names. Here is an example:</para>
- <screen>mount -t lustre mds0@tcp0:/shortfs /mnt/<long-file_system-name></screen>
+ <screen>client# mount -t lustre mds0@tcp0:/short <replaceable>/dev/long_mountpoint_name</replaceable></screen>
</section>
<section xml:id="dbdoclet.50438194_24122">
<title><indexterm><primary>operations</primary><secondary>starting</secondary></indexterm>Starting Lustre</title>
- <para>The startup order of Lustre components depends on whether you have a combined MGS/MDT or these components are separate.</para>
- <itemizedlist>
+ <para>On the first start of a Lustre file system, the components must be started in the following order:</para>
+ <orderedlist>
<listitem>
- <para>If you have a combined MGS/MDT, the recommended startup order is OSTs, then the MGS/MDT, and then clients.</para>
+ <para>Mount the MGT.</para>
+ <note><para>If a combined MGT/MDT is present, Lustre will correctly mount the MGT and MDT automatically.</para></note>
</listitem>
<listitem>
- <para> If the MGS and MDT are separate, the recommended startup order is: MGS, then OSTs, then the MDT, and then clients.</para>
+ <para>Mount the MDT.</para>
+ <note><para condition='l24'>Mount all MDTs if multiple MDTs are present.</para></note>
</listitem>
- </itemizedlist>
- <note>
- <para>If an OST is added to a Lustre file system with a combined MGS/MDT, then the startup order changes slightly; the MGS must be started first because the OST needs to write its configuration data to it. In this scenario, the startup order is MGS/MDT, then OSTs, then the clients.</para>
- </note>
+ <listitem>
+ <para>Mount the OST(s).</para>
+ </listitem>
+ <listitem>
+ <para>Mount the client(s).</para>
+ </listitem>
+ </orderedlist>
</section>
<section xml:id="dbdoclet.50438194_84876">
<title><indexterm><primary>operations</primary><secondary>mounting</secondary></indexterm>Mounting a Server</title>
<para>In this example, the MDT, an OST (ost0) and file system (testfs) are mounted.</para>
<screen>LABEL=testfs-MDT0000 /mnt/test/mdt lustre defaults,_netdev,noauto 0 0
LABEL=testfs-OST0000 /mnt/test/ost0 lustre defaults,_netdev,noauto 0 0</screen>
- <para>In general, it is wise to specify noauto and let your high-availability (HA) package manage when to mount the device. If you are not using failover, make sure that networking has been started before mounting a Lustre server. RedHat, SuSE, Debian (and perhaps others) use the <literal>_netdev</literal> flag to ensure that these disks are mounted after the network is up.</para>
+ <para>In general, it is wise to specify noauto and let your high-availability (HA) package
+ manage when to mount the device. If you are not using failover, make sure that networking has
+ been started before mounting a Lustre server. If you are running Red Hat Enterprise Linux,
+ SUSE Linux Enterprise Server, Debian operating system (and perhaps others), use the
+ <literal>_netdev</literal> flag to ensure that these disks are mounted after the network is
+ up.</para>
<para>We are mounting by disk label here. The label of a device can be read with <literal>e2label</literal>. The label of a newly-formatted Lustre server may end in <literal>FFFF</literal> if the <literal>--index</literal> option is not specified to <literal>mkfs.lustre</literal>, meaning that it has yet to be assigned. The assignment takes place when the server is first started, and the disk label is updated. It is recommended that the <literal>--index</literal> option always be used, which will also ensure that the label is set at format time.</para>
<caution>
<para>Do not do this when the client and OSS are on the same node, as memory pressure between the client and OSS can lead to deadlocks.</para>
</section>
<section xml:id="dbdoclet.50438194_69255">
<title><indexterm><primary>operations</primary><secondary>unmounting</secondary></indexterm>Unmounting a Server</title>
- <para>To stop a Lustre server, use the <literal>umount <mount point></literal> command.</para>
+ <para>To stop a Lustre server, use the <literal>umount <replaceable>/mount</replaceable> <replaceable>point</replaceable></literal> command.</para>
<para>For example, to stop <literal>ost0</literal> on mount point <literal>/mnt/test</literal>, run:</para>
<screen>$ umount /mnt/test</screen>
<para>Gracefully stopping a server with the <literal>umount</literal> command preserves the state of the connected clients. The next time the server is started, it waits for clients to reconnect, and then goes through the recovery procedure.</para>
</section>
<section xml:id="dbdoclet.50438194_57420">
<title><indexterm><primary>operations</primary><secondary>failover</secondary></indexterm>Specifying Failout/Failover Mode for OSTs</title>
- <para>Lustre uses two modes, failout and failover, to handle an OST that has become unreachable because it fails, is taken off the network, is unmounted, etc.</para>
+ <para>In a Lustre file system, an OST that has become unreachable because it fails, is taken off
+ the network, or is unmounted can be handled in one of two ways:</para>
<itemizedlist>
<listitem>
- <para> In <emphasis>failout</emphasis> mode, Lustre clients immediately receive errors (EIOs) after a timeout, instead of waiting for the OST to recover.</para>
+ <para> In <literal>failout</literal> mode, Lustre clients immediately receive errors (EIOs)
+ after a timeout, instead of waiting for the OST to recover.</para>
</listitem>
<listitem>
- <para> In <emphasis>failover</emphasis> mode, Lustre clients wait for the OST to recover.</para>
+ <para> In <literal>failover</literal> mode, Lustre clients wait for the OST to
+ recover.</para>
</listitem>
</itemizedlist>
- <para>By default, the Lustre file system uses failover mode for OSTs. To specify failout mode instead, use the <literal>--param="failover.mode=failout"</literal> option:</para>
- <screen>$ mkfs.lustre --fsname=<fsname> --mgsnode=<MGS node NID> --param="failover.mode=failout" --ost --index="OST index" <block device name></screen>
- <para>In this example, failout mode is specified for the OSTs on MGS <literal>mds0</literal>, file system <literal>testfs</literal>.</para>
- <screen>$ mkfs.lustre --fsname=testfs --mgsnode=mds0 --param="failover.mode=failout" --ost --index=3 /dev/sdb </screen>
+ <para>By default, the Lustre file system uses <literal>failover</literal> mode for OSTs. To
+ specify <literal>failout</literal> mode instead, use the
+ <literal>--param="failover.mode=failout"</literal> option as shown below (entered
+ on one line):</para>
+ <screen>oss# mkfs.lustre --fsname=<replaceable>fsname</replaceable> --mgsnode=<replaceable>mgs_NID</replaceable> --param=failover.mode=failout
+ --ost --index=<replaceable>ost_index</replaceable> <replaceable>/dev/ost_block_device</replaceable></screen>
+ <para>In the example below, <literal>failout</literal> mode is specified for the OSTs on the MGS
+ <literal>mds0</literal> in the file system <literal>testfs</literal> (entered on one
+ line).</para>
+ <screen>oss# mkfs.lustre --fsname=testfs --mgsnode=mds0 --param=failover.mode=failout
+ --ost --index=3 /dev/sdb </screen>
<caution>
- <para>Before running this command, unmount all OSTs that will be affected by the change in the failover/failout mode.</para>
+ <para>Before running this command, unmount all OSTs that will be affected by a change in
+ <literal>failover</literal> / <literal>failout</literal> mode.</para>
</caution>
<note>
- <para>After initial file system configuration, use the tunefs.lustre utility to change the failover/failout mode. For example, to set the failout mode, run:</para>
- <para><screen>$ tunefs.lustre --param failover.mode=failout <OST partition></screen></para>
+ <para>After initial file system configuration, use the <literal>tunefs.lustre</literal>
+ utility to change the mode. For example, to set the <literal>failout</literal> mode,
+ run:</para>
+ <para><screen>$ tunefs.lustre --param failover.mode=failout <replaceable>/dev/ost_device</replaceable></screen></para>
</note>
</section>
<section xml:id="dbdoclet.50438194_54138">
<para>Lustre supports multiple file systems provided the combination of <literal>NID:fsname</literal> is unique. Each file system must be allocated a unique name during creation with the <literal>--fsname</literal> parameter. Unique names for file systems are enforced if a single MGS is present. If multiple MGSs are present (for example if you have an MGS on every MDS) the administrator is responsible for ensuring file system names are unique. A single MGS and unique file system names provides a single point of administration and allows commands to be issued against the file system even if it is not mounted.</para>
<para>Lustre supports multiple file systems on a single MGS. With a single MGS fsnames are guaranteed to be unique. Lustre also allows multiple MGSs to co-exist. For example, multiple MGSs will be necessary if multiple file systems on different Lustre software versions are to be concurrently available. With multiple MGSs additional care must be taken to ensure file system names are unique. Each file system should have a unique fsname among all systems that may interoperate in the future.</para>
<para>By default, the <literal>mkfs.lustre</literal> command creates a file system named <literal>lustre</literal>. To specify a different file system name (limited to 8 characters) at format time, use the <literal>--fsname</literal> option:</para>
- <para><screen>mkfs.lustre --fsname=<file system name></screen></para>
+ <para><screen>mkfs.lustre --fsname=<replaceable>file_system_name</replaceable></screen></para>
<note>
- <para>The MDT, OSTs and clients in the new file system must use the same filesystem name (prepended to the device name). For example, for a new file system named <literal>foo</literal>, the MDT and two OSTs would be named <literal>foo-MDT0000</literal>, <literal>foo-OST0000</literal>, and <literal>foo-OST0001</literal>.</para>
+ <para>The MDT, OSTs and clients in the new file system must use the same file system name
+ (prepended to the device name). For example, for a new file system named
+ <literal>foo</literal>, the MDT and two OSTs would be named
+ <literal>foo-MDT0000</literal>, <literal>foo-OST0000</literal>, and
+ <literal>foo-OST0001</literal>.</para>
</note>
<para>To mount a client on the file system, run:</para>
- <screen>mount -t lustre mgsnode:/<new fsname> <mountpoint></screen>
+ <screen>client# mount -t lustre <replaceable>mgsnode</replaceable>:<replaceable>/new_fsname</replaceable> <replaceable>/mount_point</replaceable></screen>
<para>For example, to mount a client on file system foo at mount point /mnt/foo, run:</para>
- <screen>mount -t lustre mgsnode:/foo /mnt/foo</screen>
+ <screen>client# mount -t lustre mgsnode:/foo /mnt/foo</screen>
<note>
<para>If a client(s) will be mounted on several file systems, add the following line to <literal>/etc/xattr.conf</literal> file to avoid problems when files are moved between the file systems: <literal>lustre.* skip</literal></para>
</note>
<note>
- <para>To ensure that a new MDT is added to an existing MGS create the MDT by specifying: <literal>--mdt --mgsnode=<MGS node NID></literal>.</para>
+ <para>To ensure that a new MDT is added to an existing MGS create the MDT by specifying: <literal>--mdt --mgsnode=<replaceable>mgs_NID</replaceable></literal>.</para>
</note>
<para>A Lustre installation with two file systems (<literal>foo</literal> and <literal>bar</literal>) could look like this, where the MGS node is <literal>mgsnode@tcp0</literal> and the mount points are <literal>/mnt/foo</literal> and <literal>/mnt/bar</literal>.</para>
<screen>mgsnode# mkfs.lustre --mgs /dev/sda
ossbarnode# mkfs.lustre --fsname=bar --mgsnode=mgsnode@tcp0 --ost --index=0 /dev/sdc
ossbarnode# mkfs.lustre --fsname=bar --mgsnode=mgsnode@tcp0 --ost --index=1 /dev/sdd</screen>
<para>To mount a client on file system foo at mount point <literal>/mnt/foo</literal>, run:</para>
- <screen>mount -t lustre mgsnode@tcp0:/foo /mnt/foo</screen>
+ <screen>client# mount -t lustre mgsnode@tcp0:/foo /mnt/foo</screen>
<para>To mount a client on file system bar at mount point <literal>/mnt/bar</literal>, run:</para>
- <screen>mount -t lustre mgsnode@tcp0:/bar /mnt/bar</screen>
+ <screen>client# mount -t lustre mgsnode@tcp0:/bar /mnt/bar</screen>
+ </section>
+ <section xml:id="dbdoclet.lfsmkdir" condition='l24'>
+ <title><indexterm><primary>operations</primary><secondary>remote directory</secondary></indexterm>Creating a sub-directory on a given MDT</title>
+ <para>Lustre 2.4 enables individual sub-directories to be serviced by unique MDTs. An administrator can allocate a sub-directory to a given MDT using the command:</para>
+ <screen>client# lfs mkdir –i <replaceable>mdt_index</replaceable> <replaceable>/mount_point/remote_dir</replaceable>
+ </screen>
+ <para>This command will allocate the sub-directory <literal>remote_dir</literal> onto the MDT of index <literal>mdtindex</literal>. For more information on adding additional MDTs and <literal>mdtindex</literal> see <xref linkend='dbdoclet.addmdtindex'/>.</para>
+ <warning><para>An administrator can allocate remote sub-directories to separate MDTs. Creating remote sub-directories in parent directories not hosted on MDT0 is not recommended. This is because the failure of the parent MDT will leave the namespace below it inaccessible. For this reason, by default it is only possible to create remote sub-directories off MDT0. To relax this restriction and enable remote sub-directories off any MDT, an administrator must issue the command <literal>lctl set_param mdd.*.enable_remote_dir=1</literal>.</para></warning>
</section>
<section xml:id="dbdoclet.50438194_88980">
<title><indexterm><primary>operations</primary><secondary>parameters</secondary></indexterm>Setting and Retrieving Lustre Parameters</title>
<section xml:id="dbdoclet.50438194_17237">
<title>Setting Tunable Parameters with <literal>mkfs.lustre</literal></title>
<para>When the file system is first formatted, parameters can simply be added as a <literal>--param</literal> option to the <literal>mkfs.lustre</literal> command. For example:</para>
- <screen>$ mkfs.lustre --mdt --param="sys.timeout=50" /dev/sda</screen>
+ <screen>mds# mkfs.lustre --mdt --param="sys.timeout=50" /dev/sda</screen>
<para>For more details about creating a file system,see <xref linkend="configuringlustre"/>. For more details about <literal>mkfs.lustre</literal>, see <xref linkend="systemconfigurationutilities"/>.</para>
</section>
<section xml:id="dbdoclet.50438194_55253">
<title>Setting Parameters with <literal>tunefs.lustre</literal></title>
- <para>If a server (OSS or MDS) is stopped, parameters can be added to an existing filesystem using the <literal>--param</literal> option to the <literal>tunefs.lustre</literal> command. For example:</para>
- <screen>$ tunefs.lustre --param="failover.node=192.168.0.13@tcp0" /dev/sda</screen>
- <para>With <literal>tunefs.lustre</literal>, parameters are "additive" -- new parameters are specified in addition to old parameters, they do not replace them. To erase all old <literal>tunefs.lustre</literal> parameters and just use newly-specified parameters, run:</para>
- <screen>$ tunefs.lustre --erase-params --param=<new parameters> </screen>
- <para>The tunefs.lustre command can be used to set any parameter settable in a /proc/fs/lustre file and that has its own OBD device, so it can be specified as <literal><obd|fsname>.<obdtype>.<proc_file_name>=<value></literal>. For example:</para>
- <screen>$ tunefs.lustre --param mdt.identity_upcall=NONE /dev/sda1</screen>
+ <para>If a server (OSS or MDS) is stopped, parameters can be added to an existing file system
+ using the <literal>--param</literal> option to the <literal>tunefs.lustre</literal> command.
+ For example:</para>
+ <screen>oss# tunefs.lustre --param=failover.node=192.168.0.13@tcp0 /dev/sda</screen>
+ <para>With <literal>tunefs.lustre</literal>, parameters are <emphasis>additive</emphasis> -- new parameters are specified in addition to old parameters, they do not replace them. To erase all old <literal>tunefs.lustre</literal> parameters and just use newly-specified parameters, run:</para>
+ <screen>mds# tunefs.lustre --erase-params --param=<replaceable>new_parameters</replaceable> </screen>
+ <para>The tunefs.lustre command can be used to set any parameter settable in a /proc/fs/lustre file and that has its own OBD device, so it can be specified as <literal><replaceable>obdname|fsname</replaceable>.<replaceable>obdtype</replaceable>.<replaceable>proc_file_name</replaceable>=<replaceable>value</replaceable></literal>. For example:</para>
+ <screen>mds# tunefs.lustre --param mdt.identity_upcall=NONE /dev/sda1</screen>
<para>For more details about <literal>tunefs.lustre</literal>, see <xref linkend="systemconfigurationutilities"/>.</para>
</section>
<section xml:id="dbdoclet.50438194_51490">
<section remap="h4">
<title>Setting Temporary Parameters</title>
<para>Use <literal>lctl set_param</literal> to set temporary parameters on the node where it is run. These parameters map to items in <literal>/proc/{fs,sys}/{lnet,lustre}</literal>. The <literal>lctl set_param</literal> command uses this syntax:</para>
- <screen>lctl set_param [-n] <obdtype>.<obdname>.<proc_file_name>=<value></screen>
+ <screen>lctl set_param [-n] <replaceable>obdtype</replaceable>.<replaceable>obdname</replaceable>.<replaceable>proc_file_name</replaceable>=<replaceable>value</replaceable></screen>
<para>For example:</para>
<screen># lctl set_param osc.*.max_dirty_mb=1024
osc.myth-OST0000-osc.max_dirty_mb=32
<section xml:id="dbdoclet.50438194_64195">
<title>Setting Permanent Parameters</title>
<para>Use the <literal>lctl conf_param</literal> command to set permanent parameters. In general, the <literal>lctl conf_param</literal> command can be used to specify any parameter settable in a <literal>/proc/fs/lustre</literal> file, with its own OBD device. The <literal>lctl conf_param</literal> command uses this syntax (same as the <literal>mkfs.lustre</literal> and <literal>tunefs.lustre</literal> commands):</para>
- <screen><obd|fsname>.<obdtype>.<proc_file_name>=<value>) </screen>
+ <screen><replaceable>obdname|fsname</replaceable>.<replaceable>obdtype</replaceable>.<replaceable>proc_file_name</replaceable>=<replaceable>value</replaceable>) </screen>
<para>Here are a few examples of <literal>lctl conf_param</literal> commands:</para>
- <screen>$ mgs> lctl conf_param testfs-MDT0000.sys.timeout=40
+ <screen>mgs# lctl conf_param testfs-MDT0000.sys.timeout=40
$ lctl conf_param testfs-MDT0000.mdt.identity_upcall=NONE
$ lctl conf_param testfs.llite.max_read_ahead_mb=16
$ lctl conf_param testfs-MDT0000.lov.stripesize=2M
<para>Parameters specified with the <literal>lctl conf_param</literal> command are set permanently in the file system's configuration file on the MGS.</para>
</caution>
</section>
+ <section xml:id="dbdoclet.setparamp" condition='l25'>
+ <title>Setting Permanent Parameters with lctl set_param -P</title>
+ <para> Use the <literal>lctl set_param -P</literal> to set parameters permanently. This command must be issued on the MGS. The given parameter is set on every host using <literal>lctl</literal> upcall. Parameters map to items in <literal>/proc/{fs,sys}/{lnet,lustre}</literal>. The <literal>lctl set_param</literal> command uses this syntax:</para>
+ <screen>lctl set_param -P <replaceable>obdtype</replaceable>.<replaceable>obdname</replaceable>.<replaceable>proc_file_name</replaceable>=<replaceable>value</replaceable></screen>
+ <para>For example:</para>
+ <screen># lctl set_param -P osc.*.max_dirty_mb=1024
+osc.myth-OST0000-osc.max_dirty_mb=32
+osc.myth-OST0001-osc.max_dirty_mb=32
+osc.myth-OST0002-osc.max_dirty_mb=32
+osc.myth-OST0003-osc.max_dirty_mb=32
+osc.myth-OST0004-osc.max_dirty_mb=32 </screen>
+ <para>Use <literal>-d </literal> (only with -P) option to delete permanent parameter. Syntax:</para>
+ <screen>lctl set_param -P -d<replaceable>obdtype</replaceable>.<replaceable>obdname</replaceable>.<replaceable>proc_file_name</replaceable></screen>
+ <para>For example:</para>
+ <screen># lctl set_param -P -d osc.*.max_dirty_mb </screen>
+ </section>
<section xml:id="dbdoclet.50438194_88217">
<title>Listing Parameters</title>
<para>To list Lustre or LNET parameters that are available to set, use the <literal>lctl list_param</literal> command. For example:</para>
- <screen>lctl list_param [-FR] <obdtype>.<obdname></screen>
+ <screen>lctl list_param [-FR] <replaceable>obdtype</replaceable>.<replaceable>obdname</replaceable></screen>
<para>The following arguments are available for the <literal>lctl list_param</literal> command.</para>
<para><literal>-F</literal> Add '<literal>/</literal>', '<literal>@</literal>' or '<literal>=</literal>' for directories, symlinks and writeable files, respectively</para>
<para><literal>-R</literal> Recursively lists all parameters under the specified path</para>
<para>For example:</para>
- <screen>$ lctl list_param obdfilter.lustre-OST0000 </screen>
+ <screen>oss# lctl list_param obdfilter.lustre-OST0000 </screen>
</section>
<section xml:id="dbdoclet.50438194_63247">
<title>Reporting Current Parameter Values</title>
<para>To report current Lustre parameter values, use the <literal>lctl get_param</literal> command with this syntax:</para>
- <screen>lctl get_param [-n] <obdtype>.<obdname>.<proc_file_name></screen>
+ <screen>lctl get_param [-n] <replaceable>obdtype</replaceable>.<replaceable>obdname</replaceable>.<replaceable>proc_file_name</replaceable></screen>
<para>This example reports data on RPC service times.</para>
- <screen>$ lctl get_param -n ost.*.ost_io.timeouts
+ <screen>oss# lctl get_param -n ost.*.ost_io.timeouts
service : cur 1 worst 30 (at 1257150393, 85d23h58m54s ago) 1 1 1 1 </screen>
<para>This example reports the amount of space this client has reserved for writeback cache with each OST:</para>
- <screen># lctl get_param osc.*.cur_grant_bytes
+ <screen>client# lctl get_param osc.*.cur_grant_bytes
osc.myth-OST0000-osc-ffff8800376bdc00.cur_grant_bytes=2097152
osc.myth-OST0001-osc-ffff8800376bdc00.cur_grant_bytes=33890304
osc.myth-OST0002-osc-ffff8800376bdc00.cur_grant_bytes=35418112
</section>
<section xml:id="dbdoclet.50438194_41817">
<title><indexterm><primary>operations</primary><secondary>failover</secondary></indexterm>Specifying NIDs and Failover</title>
- <para>If a node has multiple network interfaces, it may have multiple NIDs. When a node is specified, all of its NIDs must be listed, delimited by commas (<literal>,</literal>) so other nodes can choose the NID that is appropriate for their network interfaces. When failover nodes are specified, they are delimited by a colon (<literal>:</literal>) or by repeating a keyword (<literal>--mgsnode=</literal> or <literal>--failnode=</literal> or <literal>--servicenode=</literal>). To obtain all NIDs from a node (while LNET is running), run:</para>
+ <para>If a node has multiple network interfaces, it may have multiple NIDs, which must all be
+ identified so other nodes can choose the NID that is appropriate for their network interfaces.
+ Typically, NIDs are specified in a list delimited by commas (<literal>,</literal>). However,
+ when failover nodes are specified, the NIDs are delimited by a colon (<literal>:</literal>) or
+ by repeating a keyword such as <literal>--mgsnode=</literal> or
+ <literal>--servicenode=</literal>). </para>
+ <para>To display the NIDs of all servers in networks configured to work with the Lustre file
+ system, run (while LNET is running):</para>
<screen>lctl list_nids</screen>
- <para>This displays the server's NIDs (networks configured to work with Lustre).</para>
- <para>This example has a combined MGS/MDT failover pair on mds0 and mds1, and a OST failover pair on oss0 and oss1. There are corresponding Elan addresses on mds0 and mds1.</para>
- <screen>mds0> mkfs.lustre --fsname=testfs --mdt --mgs --failnode=mds1,2@elan /dev/sda1
-mds0> mount -t lustre /dev/sda1 /mnt/test/mdt
-oss0> mkfs.lustre --fsname=testfs --failnode=oss1 --ost --index=0 \
- --mgsnode=mds0,1@elan --mgsnode=mds1,2@elan /dev/sdb
-oss0> mount -t lustre /dev/sdb /mnt/test/ost0
-client> mount -t lustre mds0,1@elan:mds1,2@elan:/testfs /mnt/testfs
-mds0> umount /mnt/mdt
-mds1> mount -t lustre /dev/sda1 /mnt/test/mdt
-mds1> cat /proc/fs/lustre/mds/testfs-MDT0000/recovery_status</screen>
- <para>Where multiple NIDs are specified, comma-separation (for example, <literal>mds1,2@elan</literal>) means that the two NIDs refer to the same host, and that Lustre needs to choose the "best" one for communication. Colon-separation (for example, <literal>mds0:mds1</literal>) means that the two NIDs refer to two different hosts, and should be treated as failover locations (Lustre tries the first one, and if that fails, it tries the second one.)</para>
- <para>Two options exist to specify failover nodes. <literal>--failnode</literal> and <literal>--servicenode</literal>. <literal>--failnode</literal> specifies the NIDs of failover nodes. <literal>--servicenode</literal> specifies all service NIDs, including those of the primary node and of failover nodes. Option <literal>--servicenode</literal> makes the MDT or OST treat all its service nodes equally. The first service node to load the target device becomes the primary service node. Other node NIDs will become failover locations for the target device.</para>
- <note>
- <para>If you have an MGS or MDT configured for failover, perform these steps:</para>
- <orderedlist>
- <listitem>
- <para>On the oss0 node, list the NIDs of all MGS nodes at <literal>mkfs</literal> time.</para>
- <screen>oss0# mkfs.lustre --fsname sunfs --mgsnode=10.0.0.1 \
- --mgsnode=10.0.0.2 --ost --index=0 /dev/sdb</screen>
- </listitem>
- <listitem>
- <para>On the client, mount the file system.</para>
- <para><screen>client# mount -t lustre 10.0.0.1:10.0.0.2:/sunfs /cfs/client/</screen></para>
- </listitem>
- </orderedlist>
- </note>
+ <para>In the example below, <literal>mds0</literal> and <literal>mds1</literal> are configured
+ as a combined MGS/MDT failover pair and <literal>oss0</literal> and <literal>oss1</literal>
+ are configured as an OST failover pair. The Ethernet address for <literal>mds0</literal> is
+ 192.168.10.1, and for <literal>mds1</literal> is 192.168.10.2. The Ethernet addresses for
+ <literal>oss0</literal> and <literal>oss1</literal> are 192.168.10.20 and 192.168.10.21
+ respectively.</para>
+ <screen>mds0# mkfs.lustre --fsname=testfs --mdt --mgs \
+ --servicenode=192.168.10.2@tcp0 \
+ -–servicenode=192.168.10.1@tcp0 /dev/sda1
+mds0# mount -t lustre /dev/sda1 /mnt/test/mdt
+oss0# mkfs.lustre --fsname=testfs --servicenode=192.168.10.20@tcp0 \
+ --servicenode=192.168.10.21 --ost --index=0 \
+ --mgsnode=192.168.10.1@tcp0 --mgsnode=192.168.10.2@tcp0 \
+ /dev/sdb
+oss0# mount -t lustre /dev/sdb /mnt/test/ost0
+client# mount -t lustre 192.168.10.1@tcp0:192.168.10.2@tcp0:/testfs \
+ /mnt/testfs
+mds0# umount /mnt/mdt
+mds1# mount -t lustre /dev/sda1 /mnt/test/mdt
+mds1# cat /proc/fs/lustre/mds/testfs-MDT0000/recovery_status</screen>
+ <para>Where multiple NIDs are specified separated by commas (for example,
+ <literal>10.67.73.200@tcp,192.168.10.1@tcp</literal>), the two NIDs refer to the same host,
+ and the Lustre software chooses the <emphasis>best</emphasis> one for communication. When a
+ pair of NIDs is separated by a colon (for example,
+ <literal>10.67.73.200@tcp:10.67.73.201@tcp</literal>), the two NIDs refer to two different
+ hosts and are treated as a failover pair (the Lustre software tries the first one, and if that
+ fails, it tries the second one.)</para>
+ <para>Two options to <literal>mkfs.lustre</literal> can be used to specify failover nodes.
+ Introduced in Lustre software release 2.0, the <literal>--servicenode</literal> option is used
+ to specify all service NIDs, including those for primary nodes and failover nodes. When the
+ <literal>--servicenode</literal>option is used, the first service node to load the target
+ device becomes the primary service node, while nodes corresponding to the other specified NIDs
+ become failover locations for the target device. An older option,
+ <literal>--failnode</literal>, specifies just the NIDS of failover nodes. For more
+ information about the <literal>--servicenode</literal> and <literal>--failnode</literal>
+ options, see <xref xmlns:xlink="http://www.w3.org/1999/xlink" linkend="configuringfailover"
+ />.</para>
</section>
<section xml:id="dbdoclet.50438194_70905">
<title><indexterm><primary>operations</primary><secondary>erasing a file system</secondary></indexterm>Erasing a File System</title>
- <para>If you want to erase a file system and permanently delete all the
- data in the filesystem, run this command on your targets:</para>
+ <para>If you want to erase a file system and permanently delete all the data in the file system,
+ run this command on your targets:</para>
<screen>$ "mkfs.lustre --reformat"</screen>
<para>If you are using a separate MGS and want to keep other file systems defined on that MGS, then set the <literal>writeconf</literal> flag on the MDT for that file system. The <literal>writeconf</literal> flag causes the configuration logs to be erased; they are regenerated the next time the servers start.</para>
<para>To set the <literal>writeconf</literal> flag on the MDT:</para>
<screen>$ mkfs.lustre --reformat --fsname spfs --mgs --mdt --index=0 /dev/<emphasis>{mdsdev}</emphasis></screen>
</listitem>
<listitem>
- <para>If you have a separate MGS (that you do not want to reformat), then add the "--writeconf" flag to <literal>mkfs.lustre</literal> on the MDT, run:</para>
- <screen>$ mkfs.lustre --reformat --writeconf --fsname spfs --mgsnode=<MGS node NID> --mdt --index=0 /dev/<emphasis>{mdsdev}</emphasis></screen>
+ <para>If you have a separate MGS (that you do not want to reformat), then add the <literal>--writeconf</literal> flag to <literal>mkfs.lustre</literal> on the MDT, run:</para>
+ <screen>$ mkfs.lustre --reformat --writeconf --fsname spfs --mgsnode=<replaceable>mgs_nid</replaceable> --mdt --index=0 <replaceable>/dev/mds_device</replaceable></screen>
</listitem>
</orderedlist>
<note>
</section>
<section xml:id="dbdoclet.50438194_16954">
<title><indexterm><primary>operations</primary><secondary>reclaiming space</secondary></indexterm>Reclaiming Reserved Disk Space</title>
- <para>All current Lustre installations run the ldiskfs file system
- internally on service nodes. By default, ldiskfs reserves 5% of the disk
- space to avoid filesystem fragmentation. In order to reclaim this space,
- run the following command on your OSS for each OST in the filesystem:</para>
+ <para>All current Lustre installations run the ldiskfs file system internally on service nodes.
+ By default, ldiskfs reserves 5% of the disk space to avoid file system fragmentation. In order
+ to reclaim this space, run the following command on your OSS for each OST in the file
+ system:</para>
<screen>tune2fs [-m reserved_blocks_percent] /dev/<emphasis>{ostdev}</emphasis></screen>
<para>You do not need to shut down Lustre before running this command or restart it afterwards.</para>
<warning>
- <para>Reducing the space reservation can cause severe performance
- degradation as the OST filesystem becomes more than 95% full, due to
- difficulty in locating large areas of contiguous free space. This
- performance degradation may persist even if the space usage drops
- below 95% again. It is recommended NOT to reduce the reserved disk
- space below 5%.</para>
+ <para>Reducing the space reservation can cause severe performance degradation as the OST file
+ system becomes more than 95% full, due to difficulty in locating large areas of contiguous
+ free space. This performance degradation may persist even if the space usage drops below 95%
+ again. It is recommended NOT to reduce the reserved disk space below 5%.</para>
</warning>
</section>
<section xml:id="dbdoclet.50438194_69998">
<title><indexterm><primary>operations</primary><secondary>replacing an OST or MDS</secondary></indexterm>Replacing an Existing OST or MDT</title>
- <para>To copy the contents of an existing OST to a new OST (or an old
- MDT to a new MDT), follow the process for either OST/MDT backups in
+ <para>To copy the contents of an existing OST to a new OST (or an old MDT to a new MDT), follow the process for either OST/MDT backups in
<xref linkend='dbdoclet.50438207_71633'/> or
- <xref linkend='dbdoclet.50438207_21638'/>.</para>
+ <xref linkend='dbdoclet.50438207_21638'/>. For more information on removing a MDT, see <xref linkend='dbdoclet.rmremotedir'/>.</para>
</section>
<section xml:id="dbdoclet.50438194_30872">
<title><indexterm><primary>operations</primary><secondary>identifying OSTs</secondary></indexterm>Identifying To Which Lustre File an OST Object Belongs</title>
</screen></para>
</listitem>
<listitem>
- <para>For Lustre 2.x filesystems, the parent FID will be of the form
- [0x200000400:0x122:0x0] and can be resolved directly using the
- <literal>lfs path2fid [0x200000404:0x122:0x0] /mnt/lustre</literal>
- command on any Lustre client, and the process is complete.</para>
+ <para>For Lustre software release 2.x file systems, the parent FID will be of the form
+ [0x200000400:0x122:0x0] and can be resolved directly using the <literal>lfs fid2path
+ [0x200000404:0x122:0x0] /mnt/lustre</literal> command on any Lustre client, and the
+ process is complete.</para>
</listitem>
<listitem>
<para>In this example the parent inode FID is an upgraded 1.x inode
git://git.whamcloud.com / doc / manual.git / blobdiff